ARTIKEL AUF DEUTSCH

Study confirms glyphosate contaminating groundwater

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Published: 17 December 2011

1.Determination of glyphosate in groundwater samples2.Roundup herbicide found in air, rain, and streams

NOTE: This study on groundwater comes not long after the news that two US Geological Survey studies had consistently found glyphosate in streams, rain and air in agricultural areas of the US.–-–-1.Analytical and Bioanalytical Chemistry2011 Nov 20Epublication ahead of printhttp://www.ncbi.nlm.nih.gov/pubmed/22101424

Determination of glyphosate in groundwater samples using an ultrasensitive immunoassay and confirmation by on-line solid-phase extraction followed by liquid chromatography coupled to tandem mass spectrometry.

Despite having been the focus of much attention from the scientific community during recent years, glyphosate is still a challenging compound from an analytical point of view because of its physicochemical properties: relatively low molecular weight, high polarity, high water solubility, low organic solvent solubility, amphoteric behaviour and ease to form metal complexes. Large efforts have been directed towards developing suitable, sensitive and robust methods for the routine analysis of this widely used herbicide. In the present work, a magnetic particle immunoassay (IA) has been evaluated for fast, reliable and accurate part-per-trillion monitoring of glyphosate in water matrixes, in combination with a new analytical method based on solid-phase extraction (SPE), followed by liquid chromatography (LC) coupled to tandem mass spectrometry (MS/MS), for the confirmatory analysis of positive samples. The magnetic particle IA has been applied to the analysis of about 140 samples ofgroundwater from Catalonia (NE Spain) collected during four sampling campaigns. Glyphosate was present above limit of quantification levels in 41% of the samples with concentrations as high as 2.5 Î¼g/L and a mean concentration of 200 ng/L. Good agreement was obtained when comparing the results from IA and on-line SPE-LC-MS/MS analyses. In addition, no false negatives were obtained by the use of the rapid IA. This is one of the few works related to the analysis of glyphosate in real groundwater samples and the presented data confirm that, although it has low mobility in soils, glyphosate is capable of reaching groundwater.

Glyphosate herbicide, known by its trade name Roundup, is commonly found in rain and rivers in agricultural areas in the Mississippi River watershed, according to two US Geological Survey studies released in August.

“It’s out there in significant levels”

Glyphosate is used in almost all agricultural and urban areas of the United States. The greatest glyphosate use is in the Mississippi River basin, where most applications are to kill weeds on genetically modified corn, soybeans and cotton. Overall, agricultural use of glyphosate has increased 8-fold from less than 11,000 tons in 1992 to more than 88,000 tons in 2007.

"Though glyphosate is the mostly widely used herbicide in the world, we know very little about its long term effects to the environment,” says Paul Capel, USGS chemist and an author on this study. “This study is one of the first to document the consistent occurrence of this chemical in streams, rain and air throughout the growing season. This is crucial information for understanding where management efforts for this chemical would best be focused.”

In these studies, glyphosate was frequently detected in surface waters, rain and air in areas where it is heavily used in the basin. The consistent occurrence of glyphosate in streams and air indicates its transport from its point of use into the broader environment.

Capel told Reuters that glyphosate is "out there in significant levels. It is out there consistently."

He said more tests were needed to determine how harmful glyphosate might be to people and animals.

Adds to mounting concerns with Roundup

The presence of glyphosate and its degradation product, aminomethylphosphonic acid (AMPA), in surface waters means that drinking water quality and aquatic wildlife may be put at risk. Studies have shown many aquatic species are affected by the herbicide and its breakdown product, and there is growing concern about the safety of the product for human health.

USGS found glyphosate in more than 60% of air and rain sampled at three locations in Mississippi, Iowa and Indiana, with AMPA found in more than 50% of samples.

Commenting on USGS’s findings, Pete Riley of United Kingdom-based GM Freeze said: “The Mississippi Basin has been subjected to glyphosate application on a massive scale for the last 15 years. As a result of this giant uncontrolled experiment, the USGS is now finding that glyphosate and its breakdown products are turning up in rainfall and rivers, and not, as Monsanto would have us think, being safely locked up in the soil. The mounting evidence on the safety and movement of glyphosate now merits a ban on GM herbicide tolerant crops.”